1. Field of the Invention
The present invention relates to a session based service, and more particularly, a group advertisement method in a SIP (Session Initiation Protocol) based message service.
2. Discussion of the Related Art
In general, a PT (Push-To) service, which is intended to provide rapid communications for service providers and mobile communication users, is a communication service in which one client transmits media data (e.g., talk burst) to one or more other clients with which a session has been established. A PT service can be a PoC (Push-to-talk over Cellular) service for transmission of voice (audio), a PTV (Push To View) service for transmission of pictures (video), or a PTD (Push To Data) service for transmission of data.
The PT service allows communication with a single recipient (1-to-1) or between groups of recipients as in a group chat session (1-to-many), and uses a session initiation protocol (SIP) to establish a session.
In the PT service, one PT client can invite clients or groups, to which clients belong, to a PT session. That is, a particular PT client selects one or more other PT clients to Invite them to the PT session. The session is then established among these PT clients. Accordingly, media data is communicated between the session-established PT clients.
The PT service provides “group advertisement”. The group advertisement denotes that one PT group designator designates a particular PT group to inform other PT clients of the existence of the PT group for use. For instance, a particular PT client may advertise (inform) about an address of a PT group (e.g., group name) to the members of the PT group, so that the PT group members can use the PT group address to communicate with each other.
The designated PT group can be divided into an unrestricted chat PT group in which a group advertisement is allowed (accepted) for every PT client, and a restricted chat PT group in which a group advertisement is allowed only for PT group members. The chat PT groups generally are generally established at a server side, e.g., by an operator or an administer, so end-users such as customers can simply join such chat groups. Here, the designator would be the operator or the administrator. Another example of the designated PT group is a pre-arranged PT group which is generally established by an individual end-user. For instance, a user of a terminal can create his own PT group composed of his family and friends as members. Here, the designator is the user who created such pre-arranged PT group.
Therefore, generally the PT group designator registers a PT group document for the corresponding PT group in an XDM (XML Database Management) server. Generally the PT group document identifies the group name/address and the members belonging to the group. A controlling PT server performing a control function can process a group advertisement request of a PT client via a SIP message based on the PT group document.
However, the PT group document according to the related art does not specify any rule or condition regarding the group advertisement, because PT service provides have not made advertising rules for the group advertisement yet. As a result, in the related art, every PT user has been unconditionally allowed to perform a group advertisement with respect to a PT group designated by the PT group designator, which causes frequent invitations to all the group members due to the over-exposure of group and group member addresses. Since any appropriate advertising rule has not be provided for the group advertisement in the related art, the PT group designator can not stably maintain and operate the PT group designated by itself. As a result, a group advertisement in the related art is performed many times and unnecessarily, without the consideration of any relevant factor such as privacy, etc. Also, the related art has a problem in that information related to the corresponding PT group to which participants belong is exposed regardless of their intentions.